Cutleaf nightshade, morelle à trois fleurs

Herbs, annual, decumbent to prostrate, unarmed, to 0.4 m, fleshy, nearly glabrous to moderately pubescent, hairs unbranched, to 2 mm, eglan­dular, rarely glandular. Leaves petiolate; petiole 0.5–2.5 cm; blade simple, elliptic to oblong, 2–5 × 1–3 cm, margins shallowly lobed to deeply and regularly pinnatifid with 3–6 lobes per side, lobe margins entire or occasionally coarsely lobed, base cuneate and decurrent. Inflorescences extra-axillary, unbranched, umbel-like, 1–6-flowered, 1–3 cm. Pedicels spreading and 0.5–1.5 cm in flower, reflexed and 0.5–1.5 cm in fruit. Flowers radially symmetric; calyx accrescent and covering base of berry, unarmed, 2–4(–7) mm, moderately pubescent, lobes deltate, reflexed; corolla white or light purple with green or pur­plish central star, stellate, 0.5–1 cm diam., with sparse interpetalar tissue; stamens equal; anthers narrowly ellipsoidal, 2.5–4 mm, dehiscent by terminal pores that open into longitudinal slits; ovary glabrous. Berries shiny dark green to purplish black, globose, 0.8–2 cm diam., glabrous, with 13–30 sclerotic granules. Seeds yellow, plump, 2–3 × 2–2.5 mm, minutely pitted. 2n = 24.

Flowering Apr–Sep. Disturbed areas, roadsides, stream banks, along railroad tracks, prairie dog towns; (0–)700–2900 m; Alta., B.C., Man., Sask.; Ariz., Calif., Colo., Idaho, Iowa, Kans., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Okla., Oreg., S.Dak., Tex., Utah, Wash., Wyo.; South America (Argentina); introduced in Europe, Africa, Australia.

Solanum triflorum is found in South America (Argentina) and is also considered to be native to central and western North America. It is occasionally adventive in the eastern United States. It is poisonous to livestock and can become a serious weed in cultivated fields, especially in the Great Plains.